I have seen it in many locations in the South, and BS is not a problem.

Never! It is tough as nails.Buff

It blooms, then defoliates, quickly grows new set of leaves and doesn't loose its vigor, keeps blooming. Then again defoliates, grows new leaves, etc. Can be 4-5 cycles per season here.
Definitely can be grown no spray even here, if you don't mind short periods of leaf loss.
Olga

The leaf loss is never significant enough to ruin the look of the bush. Mine defoliated some, but it still had lots of leaves and kept on blooming. It never looked "naked". I don't spray mine. In fact, Mutabilis does NOT like to be sprayed. The couple of times that I did in the past, he was not a happy camper.

Sandy

I saw a Mutabilis down at The Balitmore Zoo during early summer and it looked fine, I'm not recalling any particular specks of disease actually.

Then again, I remember the same trip there was a large tree with BRIGHT orange blossoms, which I swore was a pomegranate...but it was in a pot, but it looked too big that they'd pick it up and put it somewhere inside.....sooo I was like, naw couldn't be, so who knows?

How often do you have to plan on cleaning up the defoliated leaves? Daily? Weekly? I ask because I'm thinking of planting this in between our property and a (friendly) neighbor's.

I live on the Georgia/Florida border. Mine is gorgeous in the spring; good until about July/August; loses some leaves; seems to grow them back again for late summer/early fall; now (mid-October) is a tad scraggly and yellow, but still big with blooms and average leaves. I tried spraying, but didn't see a big difference, so I stopped. I just enjoy it being big and hiding an ugly electrical "thing," and wait until it's beautiful again!

Unsprayed plants here look pretty bad, but then it doesn't grow as vigorously here as elsewhere in the South, because it likes hot summers. Also I don't have much of a handle on how blackspot pressure in the LVL area compares with our own, which I think is among the worst. I think Jean said Mutabilis is OK in Nashville.

I don't think the appearance of fallen leaves on a mulched area would be a problem.

The specimen I saw at the botanical gardens in Norfolk Virginia (USDA Zone 8a) had over 50% of leaves afflicted with black spot. I was so mesmerized by the retched yellow foliage that I hardly noticed the pretty multicolored flowers. No fragrance either. Profoundly unimpressive.

Mine is still a beautiful speciman, and only lost about 25% of its leaves, mostly from the bottom and some through the middle. It actually gave it an airy look. Mine is on a property line, and the fallen leaves have blended in with the pine bark. I'll clean them up - when I get to it. Despite the fact that mine lost some leaves, it was still blooming and putting out beautiful red growth, which was visible from a distance.

Chinas can lose some leaves due to heat stress. Mutabilis has grown most of them back rather quickly. It is also common for any shrub, rose or otherwise, to shed the leaves that are old and are no longer very useful to the plant. It is not necessarily disease.

Mutabilis is a beautiful bush.

Sandy

We have a huge bush at the arboretum which is up against a lattice fence, gets only 4 to 5 hours of sun and we have barely 20% defoliation at the worst. Odd that the specimen at Norfolk is so stressed, as we are only about 15 miles south of them as the crow flies, hm.. It has bloomed all thru this long dry summer with very infrequent waterings. I just love Mutabilis!

It was definately black spot. Yellow leaves with telltale black spots. What is unusual is that this rose isn't located in their enormous rose garden. Instead it is located near the wild flower meadow in full sun with maximum air flow. Under these conditions a "disease resistant" rose should have been clean as a whistle. It might be resistant to powdery mildew and rust, but not black spot.

That's really strange, because I don't have blackspot issues with Mutabilis, and I live in the blackspot capitol of the world. I know that mine takes some hits from the neighbors irrigation system at night.

I have been told by some rose nursery people that once in awhile there are other plants that can cause insect and disease issues with roses. My intention at that time was to combine some roses with butterfly attracting plants. I'll have to research it further. Maybe some of those wildflowers caused their Mutabilis to suffer some issues.

It is also possible their Mutabilis suffers from rose mosaic virus, which would make it disease prone. It wouldn't have to show any symptoms. I've had several roses that tested positive (from a lab) that had no leaf symptoms, but were poor growers and always disease prone. When I was able to obtain a virus free version, it was like night and day.

Sandy

I've seen more cercospora than blackspot here at the arboretum in DC, and then only on the plants sited in the heaviest, wettest soils or in more shade (or both), and still then only defoliating 25-30% at most (not so that you'd pay it much mind, really). Plants sited in good sun with better air circulation (even when massed together) exhibit such good health that you couldn't find a spotted leaf if you tried. None of these have ever been sprayed.

There is a fragrance, if you smell the newly open blooms at the orange/apricot stage. It is fruity and lovely, though very delicate.

I'm no spray and I'm in hot and humid south Louisiana. I've had my Mutabilis for about five years now. Has never had blackspot, or leaf loss, continuous blooming, and smells heavenly.

For roses that have blackspot (ones out in the open), I keep them looking good with a leaf blower that gets rid of all the yellow leaves, and really does a good job. I have no idea if that spreads the spores more, but have been doing this for years on roses that are in a position of visibility, and not so much of a landscape shrub like most of mine.

That's so funny - I started doing exactly the same thing with the most spotted one, too! And so far, it seems to be working well; the plant is filling itself in again, if my eyes aren't playing tricks.

Stefan

You will probably have more problems with blackspot than those in the South. This rose likes it hot.